This study was conducted to investigate learners’ perceptions and the impacts of a theme-based teaching approach on children’s levels of interests in an English course for primary ESL students in Hong Kong in a non-school setting. A total number of 88 participants (including 76 grade 4 and 5 children and 12 course tutors) were involved. To discover if the children became more interested in learning English after the course, their perceptions of theme-based teaching, and their opinions of the themes chosen for the English course, data were collected from both the children (through the pre- and post-course questionnaires, and semi-structured interviews) and the course tutors (through the tutors’ questionnaires). The major finding is that theme-based teaching in this study could not make learners become more interested in learning English unless teachers were able to use interesting activities and suitable materials in their lessons. The themes of the course should suit the proficiency level, wants and needs of the learners and be relevant to their daily lives. Before the course begins, a placement test should be administered to ascertain the current language level of the learners. At the end of the course, evaluation should be made to assess the effectiveness of the course.[Electronic Journal of Foreign Language Teaching Copyright © Centre for Language Studies of the National University of Singapore. The journal web site is located at http://e-flt.nus.edu.sg]